Liquid tooth cleaning gel

ABSTRACT

The present invention relates to a liquid transparent tooth cleaning composition containing silica polishing components, humectant and water. The humectant includes sorbitol (a), glycerol (b) and polyethylene glycol (c) in a weight ratio of (a) to (b) to (c) of 10:(7 to 8):(0.5 to 1.5).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 U.S.C. § 371of international application PCT/EP99/07043 filed on Sep. 22, 1999, theinternational application not being published in English. Thisapplication also claims priority under 35 U.S.C. § 119 to DE 198 45247.0 filed on Oct. 1, 1998.

This invention relates to liquid tooth cleaning preparations containingpolishes, humectants and water which are substantially transparent orclear and which show favorable Theological behavior for dispensing fromsmall flexible plastic bottles.

BACKGROUND OF THE INVENTION

Liquid tooth cleaning preparations which can be dispensed under lightpressure from small flexible plastic bottles are already known, forexample from WO 94/01080 A1. These products are white or opaque inappearance. In order to formulate transparent or clear products, theliquid carrier of water, humectants and optionally dissolved ingredientsmust have a refractive index similar to the polish. WO 95/22958, forexample, describes a transparent formulation which contains more than50% by weight of sorbitol. However, the transparency of these liquidtooth gels does not show satisfactory stability to low temperatures. WO94/01080 A1 also describes transparent liquid tooth cleaningpreparations which contain ca. 21% by weight of sorbitol, 30% by weightof glycerol and 5% by weight of ethanol. These known liquid toothcleaning preparations have very low viscosities of well below 10,000mPa·s (25° C.).

The problem addressed by the present invention was to provide a liquidtooth cleaning preparation which, although remaining transparent at lowtemperatures, would not be too liquid and, when applied to a toothbrush,would not sink too quickly or too deeply into the bristles.

The problem stated above has been solved by the use of a specifichumectant mixture.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a liquid transparent tooth cleaningpreparation containing

10 to 15% by weight of silica polishing components,

55 to 70% by weight of humectants (a+b+c),

15 to 30% by weight of water and

2 to 10% by weight of other toothpaste ingredients,

characterized in that a mixture of sorbitol (a), glycerol (b) andpolyethylene glycol (c) in a ratio by weight of (a) to (b) to (c) of10:(7-8):(0.5-1.5) is present as the humectant.

Liquid in the context of the present invention means a viscosity of ca.10,000 to 100,000 mPa·s (as measured at 20° C. with a Brookfield RVFrotational viscosimeter, spindle ¾ at 4 r.p.m. corresponding to a shearrate D of 4 s⁻¹) which provides for easy dispensing from a smallflexible bottle and ensures that the gel sinks slowly into the bristlesof the toothbrush.

Transparency should be at least so high that text with a letter heightof ca. 4 mm and a letter width of 3 mm is still easy to read through aca. 1 cm thick layer of the tooth gel (for example in a clear glass cellwith an edge length of 1×1×4 cm).

Suitable silica polishing components are any silica gels, silicahydrogels and precipitated silicas known as polishes. Silica gels areobtained by reacting sodium silicate solutions with strong aqueousmineral acids to form a hydrosol, ageing to form the hydrogel, washingand drying. If drying is carried out under moderate conditions to awater content of 15 to 35% by weight, the so-called silica hydrogelsknown, for example, from U.S. Pat. No. 4,153,680 are obtained. Drying towater contents below 15% by weight results in irreversible shrinkage ofthe previously loose structure of the hydrogel to the dense structure ofthe so-called xerogel. Silica xerogels are described, for example, inU.S. Pat. No. 3,538,230.

A second particularly suitable group of silica polishing agents are theprecipitated silicas. Precipitated silicas are obtained by precipitationof silica from dilute alkali metal silicate solutions by addition ofstrong acids under conditions which preclude aggregation to the sol andgel. Suitable processes for the production of precipitated silicas aredescribed, for example, in DE-OS 25 22 486 and in DE-OS 31 14 493. Aparticularly suitable precipitated silica is that produced in accordancewith DE-OS 31 14 493 which has a BET surface of 15 to 110 m²/g, aparticle size of 0.5 to 20 μm (at least 80% by weight of the primaryparticles should be below 5 μm in size) and a viscosity in the form of a30% glycerol/water (1:1) dispersion of 30 to 60 Pa·s (20° C.) and whichis used in a quantity of 10 to 20% by weight, based on the toothpaste.In addition, particularly suitable precipitated silicas of this typehave rounded corners and edges and are commercially obtainable under thename of Sident®12 DS (DEGUSSA).

Other precipitated silicas of this type are Sident 8 (DEGUSSA) andSorbosil AC 39 (Crosfield Chemicals). These silicas are distinguished bya weaker thickening effect and a slightly larger mean particle size of 8to 14 μm for a specific BET surface of 40 to 75 m²/g and areparticularly suitable for liquid tooth gels according to the presentinvention.

Other polishes, particularly those with a refractive index differingfrom 1.45 μm by more than 0.1, are preferably not present at all or arepresent at most in quantities of less than 2% by weight.

Of crucial importance to the rheology and transparency of the liquidtooth cleaning gels according to the invention is the composition of theliquid carrier phase of water and humectants. The total quantity of 55to 70% by weight of humectants is composed of sorbitol (a), glycerol (b)and polyethylene glycol (c) in a relatively narrow quantity ratio of (a)to (b) to (c) of 10:(7-8):(0.5-1.5). Accordingly, for a preferredsorbitol content of 30 to 35% by weight, the glycerol content is 21 to28% by weight and the polyethylene glycol content 1.5 to 5.25% byweight.

Water (d) and humectant (a+b+c) are preferably present in a ratio byweight of (d):(a+b+c)=1:(2-3). For a preferred content of 55 to 65% byweight of humectants, the water content is 20 to 25% by weight. Thewater content is the sum of the water introduced by raw materials suchas, for example, 70% sorbitol or 86% glycerol and the water separatelyadded. The quantities of sorbitol and glycerol mentioned are based onwater-free active substance.

In addition to the compulsory components mentioned, the tooth cleaninggels according to the invention may contain other toothpaste ingredientswhich, in type and quantity, do not adversely affect transparency. Suchingredients are, for example, binders, surfactants, flavors, substancesactive against diseases of the teeth and gums, for example fluorinecompounds, scale inhibitors, antibacterial agents (for examplebiguanides, Triclosan), vitamins, panthenol and other active substances.

Finally, the transparent tooth cleaning gels according to the inventionare also eminently suitable for conversion into attractive-lookingproducts by soluble dyes and/or colored pigments. Particularly suitablecolored pigment particles are the colored silica particles commerciallyavailable, for example, under the names of Sorbosil BFG 51, BFG 52 andBFG 53 and Sorbosil SD 2352. Mixtures of differently colored pigmentparticles may also be used. These silica gel particles colored, forexample, bright orange, red or blue may be present in the tooth cleaninggels according to the invention in quantities of 0.1 to 1.0% by weight.

Suitable binders are, for example, natural and/or syntheticwater-soluble polymers, such as alginates, carrageenates, tragacanth,starch and starch ethers, cellulose ethers such as, for example,carboxymethyl cellulose (Na salt), hydroxyethyl cellulose, methylhydroxypropyl cellulose, guar, acacia gum, agar agar, xanthan gum,succinoglycan gum, locust bean gum, pectins, water-soluble carboxyvinylpolymers (for example Carbopol® types), polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycols, more particularly those withmolecular weights of 1,500 to 1,000,000.

Particularly suitable binders are xanthan gum, carboxymethyl cellulose,polyvinyl pyrrolidone and mixtures of these water-soluble polymers whichmay be present in a quantity of up to 0.5% by weight.

Suitable surfactants are, for example, sodium alkyl sulfates containing12 to 18 carbon atoms in the alkyl group. These compounds also have anenzyme-inhibiting effect on the bacterial metabolism of tartar. Othersuitable surfactants are alkali metal salts, preferably sodium salts ofalkyl polyglycol ether sulfate containing 12 to 16 carbon atoms in thelinear alkyl group and 2 to 6 glycol ether groups in the molecule, oflinear alkane (C₁₂₋₁₈) sulfonate, of sulfosuccinic acid monoalkyl(C₁₂₋₁₈) esters, of sulfated fatty acid monoglycerides, sulfated fattyacid alkanolamides, sulfoacetic acid alkyl (C₁₂₋₁₆) esters, acylsarcosines, acyl taurides and acyl isethionates containing 8 to 18carbon atoms in the acyl group. Zwitterionic, ampholytic and nonionicsurfactants, for example ethoxylates of fatty acid mono- anddiglycerides, of fatty acid sorbitan esters and alkyl (oligo)glucosides,are also suitable.

Sodium lauryl sulfate and a mixture of sodium lauryl sulfate andCocoamidopropyl Betaine are particularly suitable.

Flavors and sweeteners are normally used for flavoring. Suitable flavorsare, for example, peppermint oil, spearmint oil, eucalyptus oil, aniseedoil, fennel oil, caraway oil, methyl acetate, cinnamaldehyde, anethol,vanillin, thymol and other natural or nature-identical essential oils oreven synthetic flavors.

Suitable sweeteners are, for example, saccharin sodium, sodiumcyclamate, sucrose, lactose, maltose or fructose.

Other typical toothpaste ingredients are, for example,

preservatives and antimicrobial agents, for example p-hydroxybenzoicacid methyl, ethyl or propyl ester, sodium sorbate, sodium benzoate,bromochlorophene, Triclosan, hexetidine, phenyl salicylate, biguanides,for example chlorhexidine, and peroxides;

fluorine compounds such as, for example, Na fluoride, zinc fluoride, Namonofluorophosphate, amine fluoride, etc.

buffering agents, for example primary, secondary or tertiary alkalimetal phosphates, citric acid/Na citrate,

wound-healing and anti-inflammatory agents such as, for example, urea,allantoin, panthenol, alkali metal thiocyanates, camomile-based activeprinciples (azulene) and acetylsalicylic acid derivatives;

vitamins such as, for example, retinol, tocopherol or ascorbic acid and

mineral salts such as, for example, manganese, zinc or magnesium salts.

All these optional toothpaste ingredients together are present in thetooth gels according to the invention in a quantity of about 2 to 10% byweight.

The following Examples are intended to illustrate the invention.

EXAMPLES

Liquid tooth cleaning gels with the following composition were prepared:

1 2 3 4 5 6 Sident 12 SPLS 12 12 12 12 12 12 Sipernat 320 DS — — — — 0.5— Sorbosil BFG 51 0.1 0.1 0.1 0.1 0.1 0.1 Sorbitol 33.6 33.6 33.6 33.633.6 33.6 Glycerol 24.3 24.3 23.9 24.3 23.9 23.9 Polyethylene glycol 4003.8 3.8 3.8 3.8 3.8 3.8 Keltrol F — 0.15 — — — 0.2 Blanose 9-M-31-XF — —— — 0.2 — Blanose 12-M-31-P — — 0.25 0.25 — — Luviskol K30 — 0.01 — —0.02 — Texapon K12 0.5 0.5 0.5 0.5 0.5 0.5 Tego Betain F50 0.72 0.720.72 0.72 0.72 0.72 Cremophor RH60 — — — — — — Tagat S — — — — — —Flavor 0.8 0.8 0.8 0.8 0.8 0.8 Na saccharin 0.25 0.25 0.25 0.25 0.250.25 Panthenol — — — — — — Retinol palmitate — — — — — — Na₂PO₃F 1.1 1.11.1 1.1 1.1 1.1 Water to to to to to to 100 100 100 100 100 100Viscosity (20° C.), Pa.s 27.5 19.5 20.0 22.5 10.0 32.5 7 8 9 10 11 12 13Sident 12 SPLS 12 12 12 12 12 12 12 Sipernat 320 DS — 0.5 1.0 0.5 0.50.5 — Sorbosil BFG 51 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Sorbitol 33.6 33.633.6 33.6 33.6 33.6 33.6 Glycerol 24.3 23.9 23.9 23.9 23.9 23.9 23.9Polyethylene glycol 3.5 3.5 3.5 3.5 3.5 3.5 3.5 400 Keltrol F 0.18 — — —— — — Blanose 9-M-31-XF — 0.2 0.2 0.25 — 0.13 0.2 Blanose 12-M-31-P — —— — — — Luviskol K30 — — — — — — Texapon K12 0.5 0.5 0.5 0.5 0.5 0.5 0.5Tego Betain F50 0.72 0.72 0.72 0.72 0.72 0.72 0.72 Cremophor RH60 — — —— — — 0.2 Tagat S — — 0.5 — — — — Flavor 0.8 0.8 1.0 0.8 0.8 0.8 0.8 Nasaccharin 0.25 0.25 0.25 0.25 0.25 0.25 0.25 Panthenol — 0.13 0.13 — — —Retinol palmitate — 0.018 0.018 — — — — Na₂PO₃F 1.1 1.1 1.1 1.1 1.1 1.11.1 Water to to to to to to to 100 100 100 100 100 100 100 Viscosity26.0 21.25 22.5 20.0 37.0 37.0 18.75 (20° C.), Pa.s

All the Examples represent transparent gels which retain theirtransparency even after storage for 4 weeks at 25° C.

The following commercial products were used:

Sident® 12 SPLS:

precipitated silica, specific surface (BET) 80 m²/g, manufacturer:DEGUSSA AG

Sipernat® 320 DS:

precipitated silica, specific surface (BET) 170 m²/g, manufacturer:DEGUSSA AG

Sorbosil® BFG 51:

colored, agglomerated precipitated silica, mean particle size 310 μm(min. 90% 106-710 μm)

Keltrol® F:

xanthan gum, manufacturer: KELCO, Brussels

Blanose® 9-M-31-XF:

Na carboxymethyl cellulose, degree of subst. 0.8-0.95, viscosity 100-300mPa·s (1%), manufacturer: HERCULES

Blanose® 12-M-31-XP:

Na carboxymethyl cellulose, degree of subst. 1.2, viscosity 100-300mPa·s (1%), manufacturer: HERCULES

Luviskol® K30:

polyvinyl pyrrolidone, MW ca. 40,000, manufacturer: BASF AG

Texapon® K12:

Na lauryl sulfate (HENKEL KGaA)

Tego Betain® F50:

N,N-dimethyl-N-cocoamidopropyl ammonium acetobetaine (ca. 36% AS),manufacturer: TEGO Cosmetics

Cremophor® RH 60:

PEG 60 Hydrogenated Castor Oil (BASF AG)

Tagat® S:

polyoxyethylene-(20)-glycerol monostearate, manufacturer TEGO Cosmetics

What is claimed is:
 1. A liquid tooth cleaning composition in the formof a transparent gel comprising: (a) 10 weight percent to 15 weightpercent of one or more silica polishing components, based on The totalweight of the composition; (b) 55 weight percent to 70 weight percent ofhumectants, based on the total weight of the composition, wherein thehumectants are sorbitol, glycerol and polyethylene glycol in a weightratio of the sorbitol to the glycerol to the polyethylene glycol of10:(7 to 8):(0.5 to 1.5); and (c) 15 weight percent to 30 weight percentof water, based on the total weight of the composition.
 2. The liquidtooth cleaning compositions of claim 1 wherein the water (c) and thetotal amount (x) of the sorbitol, glycerol and polyethylene glycol arepresent in a weight ratio of (c) to (x) of 1:(2 to 3).
 3. The liquidtooth cleaning composition of claim 2 further comprising one or moretoothpaste ingredients wherein the toothpaste ingredients comprise oneor more binders, surfactants, flavorants, substances active againstdiseases of teeth or gums, or combinations thereof.
 4. The liquid toothcleaning composition of claim 3 wherein the toothpaste ingredients arepresent in an amount of 2 weight percent to 10 weight percent based onthe total weight of the composition.
 5. The liquid tooth cleaningcomposition of claim 4 further comprising from 0.1 weight percent to 1.0weight percent of colored silica particles, based on the total weight ofthe composition.
 6. The liquid tooth cleaning composition of claim 5wherein the binders are present in the composition in an amount of up to0.5 weight percent and wherein the binders are selected from the groupconsisting of xanthan gum, carboxymethyl cellulose, polyvinylpyrrolidone and combinations thereof.
 7. The liquid tooth cleaningcomposition of claim 6 wherein the composition comprises one or more ofthe substances active against diseases of the teeth or gums selectedfrom the group consisting of fluorine compounds, antimicrobial agents,vitamins, mineral salts, and combinations thereof.
 8. The liquid toothcleaning composition of claim 1 further comprising 2 weight percent to10 weight percent of additional toothpaste ingredients based on thetotal weight of the composition.
 9. The liquid tooth cleaningcomposition of claim 8 wherein the additional toothpaste ingredientscomprise one or more binders, surfactants, flavorants, substances activeagainst diseases of teeth or gums, or combinations thereof.
 10. Theliquid tooth cleaning composition of claim 1 further comprising up to0.5 weight percent based on the total weight of the composition ofxanthan gum, carboxymethyl cellulose, polyvinyl pyrrolidone orcombinations thereof.
 11. The liquid tooth cleaning composition of claim1 further comprising one or more active substances selected from thegroup consisting of fluorine compounds, antimicrobial agents, vitamins,mineral salts and combinations thereof.
 12. The liquid tooth cleaningcomposition of claim 1 further comprising from 0.1 weight percent to 1.0weight percent of colored silica particles.